Combustion chamber system having an improved valve arrangement

ABSTRACT

An intake and exhaust system for use with internal combustion engines that uses two intake valves and one exhaust valve for each engine cylinder. The three valves are preferably round and spaced around the cylinder centerline in the cylinder head. The two intake valves may be spaced closer to the exhaust valve than to each other. The two intake valves may, alternatively, be spaced closer to each other than to the exhaust valve and two spark plugs may be provided, each lying between an intake valve and the exhaust valve. For best results, the two intake valves have substantially equal diameters, with the diameter of the exhaust valve having a ratio to the diameter of an intake valve of from about 1:1 to about 1:1.2. The head has three substantially hemispheric depressions each housing one of said valves. Squish areas are preferably provided between each pair of adjacent valves around the combustion chamber periphery. This invention provides a fast and uniform lean burn, permits use of a high compression ratio and lower octane, unleaded gasoline and provides improved thermal efficiency.

This is a continuation-in-part of application Ser. No. 07/995,785 filedon Dec. 23, 1992, now U.S. Pat. No. 5,313,921.

BACKGROUND OF THE INVENTION

This invention relates in general to improvements in internal combustionengines and, more specifically, to an improved cylinder head and pistonarrangement with an improved valve and spark plug layout for use inthose engines.

A great many different intake and exhaust valve arrangements have beendeveloped over the years for use in internal combustion engines, inparticular for use in automobiles. Most such engines use one intakevalve and one exhaust valve at each cylinder with a single spark plug.The prior art arrangements utilize exhaust area intake area in the rangeof over 65%. A great deal of effort has gone into optimizing the sizingand placement of the valves, the shape of the combustion chamber and thelike. Since there is a great need for improvements in automobile fuelefficiency while maintaining or improving performance, a wide variety ofdifferent valve and spark plug configurations and arrangements have beendesigned and tested. In some of these, multiple valves and spark plugshave been used.

An arrangement of four valves per cylinder, two intake valves and twoexhaust valves, has been disclosed, for example, by Akana in U.S. Pat.No. 3,411,490. Today, a number of high performance automobiles use fourvalve systems, with one or more spark plugs. In these high performanceautomobiles, several spark plugs may be provided around the periphery ofthe combustion chamber with an additional spark plug centrally located.Manufacture and operation of these four valve, multiple spark plugengines is complex and expensive and requires complex computer controlfor efficient operation.

Weslake in U.S. Pat. No. 2,652,039 describes a complex cylinder headarrangement for an internal combustion engine having a wedgeshapedcombustion chamber adjacent to the cylinder feeding into a cylinderchamber above the piston. The combustion chamber has an intake valve, anexhaust valve and a single spark plug. A second intake valve is providedin the cylinder chamber. A weak mixture of air and fuel enters thecombustion chamber, combustion begins and a rich mixture enters throughthe cylinder chamber and adds to the original combusting mixture. Thisvery complex system appears to have been unsuccessful and to never havebeen brought into production.

Another three valve system is described by Von Segern et al in U.S. Pat.No. 3,443,552. Here, a basically conventional cylinder head having asingle intake valve and a single exhaust valve with a primary,conventional, combustion chamber is provided. In addition, a centrallylocated auxiliary chamber is located on the cylinder axis away from thecylinder in gas flow communication with the primary combustion chamber.The auxiliary chamber has a single intake valve and a spark plug.Combustion begins in the auxiliary chamber, spreads to the maincombustion chamber where added fuel mixture is introduced. Again, thisis a complex and cumbersome system that appears to have been found to beimpractical.

Thus, while a great number of different arrangements of multiple valvesand/or multiple spark plugs have been designed, none have provided anoptimum combination of structural simplicity, maximum fuel efficiencyand highest performance. Thus, despite the crowded nature of theautomobile engine fuel and air introduction and exhaust removal art,there remains a continuing need for improvements providing greateroverall efficiency at lowest cost.

It is, therefore, an object of this invention is to provide a simple,easily manufactured internal combustion engine combustion chamber systemhaving increased operating efficiency. Another object is to provide suchas system that provides both increased fuel efficiency and higherperformance. A further object is to provide such a system with highthermal efficiency. Yet another object is to provide a system capable ofoperating at high compression ratios with a variety of different fuels.

SUMMARY OF THE INVENTION

The above-noted objects, and others, are accomplished, basically, by athree valve combustion chamber system for use with internal combustionengine containing a piston and a cylinder head forming a combustionchamber therebetween. The system comprises three valves in the cylinderhead, spaced around the cylinder axis, two of the valves adapted to actas intake valves and the third as an exhaust valve. The two intakevalves preferably have the same diameter and surface area, with theexhaust valve preferably having the same or slightly greater diameter.The ratio of total exhaust valve cross-sectional area/total intake valvecross-sectional area is ideally less than 65% and can be in the range of50% to 65%.

In a first version, three peripheral spark plugs are substantiallycentrally located in the areas surrounded by adjacent valves and theedge of the combustion chamber. A central, fourth, spark plug may belocated substantially on the cylinder axis, surrounded by the threevalves. A second version has a single central spark plug locatedsubstantially on the cylinder axis, surrounded by the three valves. Ifdesired, the system of this invention may be used in a diesel or otherengine using an ignition system other than a spark plug.

The cylinder head surface forming one side of the combustion chamber hashemispheric depressions containing each of the valves, with the pistonhaving approximately flat areas corresponding to the approximately flatareas on the cylinder head located between adjacent valves and the edgeof the combustion chamber. These opposed flat areas are configured sothat as the flat piston and head areas closely approach each otherduring engine operation a very efficient "squish" area is created. Thisarrangement substantially improves combustion and fuel efficiency.

In a preferred embodiment, the three valves may be located towards oneside of the combustion chamber with the space between each intake valveand the exhaust valve being less than the distance between the twointake valves. The single central spark plug (or other ignition device)is positioned approximately on the cylinder axis.

In another preferred embodiment, wo equally spaced intake valves arepositioned to one side of the combustion chamber, with a single exhaustvalves to the other side and two spark plugs, each positioned outwardlyof a line between the center of the exhaust valve and the center of anintake valve. The intake valves and spark plugs are symmetricallylocated on the sides of a line drawn through the center of the exhaustvalve and equally spaced between the intake valves. Squish areas arelocated along the edges of the combustion chamber between each adjacentpair of valves. Optimally, the squish areas between the exhaust valveand each intake valve has a substantially straight edge, approximatelyparallel to a line drawn between the centers of the exhaust valve andthe intake valve.

BRIEF DESCRIPTION OF THE DRAWING

Details of the invention, and of certain preferred embodiments thereof,will be further understood upon reference to the drawing, wherein:

FIG. 1 is a plan view of the face of a cylinder head combustion chamber,showing a first embodiment of this invention;

FIG. 2 is a section view, taken substantially on line 2--2 in FIG. 1;

FIG. 3 is a plan view similar to FIG. 1 but showing a second embodimentof the invention;

FIG. 4 is a plan view of a piston face configuration useful with thisinvention; and

FIG. 5 is a plan view similar to FIG. 1 but showing a third embodimentof the invention.

FIG. 6 is a plan view similar to FIG. 1 but showing a fourth embodimentof the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, there is seen a cylinder head 10 having arecessed combustion chamber 12. Head 10 has a number of conventionalbolt holes, vents and the like 11 for attachment of the head to theengine block (not shown) and other purposes. Two intake valves 14 opento allow entry of air or an air-fuel mixture into combustion chamber andclosed during combustion. One exhaust valve 16 is closed duringcombustion and opens to allow egress of exhaust gases. Optimally, thefaces of valves 14 and 16 are circular and the three valves aresubstantially uniformly arranged around the cylinder and combustionchamber axis. The shafts may be canted to the cylinder centerline orvertical; that is, parallel to the cylinder centerline, as desired.

The faces of intake valves 14 preferably have the same area so thatidentical open areas are provided when the valves open and gas flowtherethrough is uniform in pattern and volume for optimum efficiency.Exhaust valve 16 ideally has a diameter equal to or slightly greaterthan that of an intake valve 14, preferably a diameter ratio of fromabout 1:1 to about 1:1.2. The ratio of total exhaust valvecross-sectional area/total intake valve cross-sectional area is ideallyless than 65% and can be in the range of 50% to 65%.

The utilization of the small exhaust port cross-sectional area andvalves provides high exhaust gas velocity, on the order of 450 ft/sec.Intake gas velocity, depending on mass, volume and/or the presence offuel would be in the 225 to 300 ft/sec range. This configuration yieldsexcellent operating characteristics, including throttle response,exhaust gas scavenging, charge purity and octane variation tolerance.Improved thermal efficiency allows for significantly reduced heattransfer.

In the embodiment of FIG. 1, one central spark plug 18. A central sparkplug 18 is shown located substantially on the cylinder centerline andmay extend above the surface of the combustion chamber 12, in thepreferred arrangement, as shown or may be recessed slightly below thesurface, if desired.

In the alternative embodiment shown in FIG. 3, three peripheral sparkplugs 20 are used. While optimum efficiency may in some instances by theaddition of a fourth spark plug centrally located in the FIG. 3embodiment, the embodiment of FIG. 3 is less costly and in many casesprovides more or at least sufficient efficiency.

If desired, only a single central spark plug 18 may be used.

FIG. 4 shows the face of a piston 24 optimized for use with thecombustion chamber 12 arrangement shown in FIGS. 1-3. For optimumcombustion a "squish" area is often desired between portions of theopposed faces of piston 24 and combustion chamber 12. In that case, theareas 22 are flat and slightly tapered away from piston toward thecombustion chamber centerline and the corresponding areas 26 aresimilarly flat and slightly tapered so that those areas closely approacheach other as piston 24 makes its closest approach to combustion chamber12 during engine operation, squeezing the fuel/air mixture in thoseareas toward the center of combustion chamber 12. Areas 22 and 26 lieapproximately perpendicular to the centerline of the combustion chamberand cylinder. This "squish" effect has been found to improve combustionefficiency. Recessed areas 28 are formed in the face of piston 24 aroundcentral pad 30 to provide the desired compression ratio in conjunctionwith the squish areas. Recessed areas 28 are sized to provide thedesired compression ratio in conjunction with the squish areas.

FIG. 5 shows a plan view of another embodiment of the combustion chambersystem. Here, the combustion chamber 12 in cylinder head 10 has agenerally similar configuration to that shown in FIG. 1, but with adifferent valve arrangement. Intake valves 14 are positioned closer toexhaust valve 16 than to each other. The size relationship among thevalves is the same as described above. Squish plates 22 of the sortdescribed above are provided between adjacent valves, with the squishplate between the two intake valves 14 being larger in area than thatbetween each intake valve 14 and the exhaust valve 16. The embodimentshown in FIG. 5 is particularly useful in permitting an offset pushrodarrangement for operating the valves. If desired, three spark plugs 18could be used, spaced around the periphery between each adjacent pair ofvalves, as shown in FIG. 3. Or, three spark plugs oriented as shown inFIG. 3 plus a centrally located plug as seen in FIG. 1 could be usedtogether.

FIG. 6 shows a plan view of another embodiment of the combustion chambersystem. Here, the combustion chamber 12 in cylinder head 10 has agenerally similar configuration to that shown in FIG. 1, but with adifferent valve arrangement. Two intake valves 14 are positioned to oneside of chamber 12, with exhaust valve 16 to the other side. Two sparkplus 18 are located between exhaust valve 16 and each intake valve 14.Each spark plug 18 is positioned outwardly of a line drawn between thecenter of exhaust valve 16 and each intake valve 14. A line of symmetrycan be drawn from the center of exhaust valve between and equally spacedfrom intake valves 14. The combustion on one side of that line ofsymmetry is a mirror image of the other side. For optimum operation,squish areas 22 are provided between each adjacent pair of valves, withthe edge of the squish areas between exhaust valve 16 and each intakevalve 14 being a substantially straight line drawn approximatelyparallel to a line drawn through the centers of the exhaust valve 16 andan intake valve 14. While the arrangement shown with two spark plugs inFIG. 6 is preferred, if desired three peripheral plugs as shown in FIG.3 and/or a central plug as shown in FIG. 1 could be used.

While certain preferred materials, dimensions and arrangements have beendescribed in detail in conjunction with the above description ofpreferred embodiments, those can be varied, where suitable, with similarresults. For example, in the embodiment shown in FIG. 6, a single sparkplug could be used at the center of the cylinder (as shown in FIG. 5)instead of the two spark plugs shown. Other applications, variations andramifications of this invention will occur to those skilled in the artupon reading this disclosure. Those are intended to be included withinthe scope of this invention, as defined in the appended claims.

I claim:
 1. An improved combustion chamber system for use with internalcombustion engine having at least one piston and a cooperating cylinderhead forming a combustion chamber therebetween, which comprises:threevalves in the head at the combustion chamber, said valves being arrangedaround an axis of the cylinder; two of the valves having substantiallyequal areas and adapted to act as intake valves; the third of saidvalves having an area equal to, or slightly greater than, the area ofone of the intake valves, the third valve being adapted to act as anexhaust valve; said two intake valves being spaced a greater distancefrom each other than from said exhaust valve; said piston having agenerally planar surface adjacent to said head forming one wall of thecombustion chamber; and at least one ignition means for igniting anair/fuel mixture in the combustion chamber, said ignition means locatedentirely within said head without extending below the plane of saidpiston's generally planar surface at any point during engine operation.2. The system according to claim 1 wherein said ignition means comprisesa single spark plug located in said head approximately at said cylinderaxis.
 3. The system according to claim 1 wherein each of said valves issubstantially circular and the ratio of diameters of the intake valvesto the diameter of the exhaust valve are from 1:1 to 1:1.2.
 4. Thesystem according to claim 1 wherein said head includes three hemisphericdepressions each housing one of said valves.
 5. The system according toclaim 1 wherein the exhaust area/intake area ratio is less thanapproximately 65%.
 6. The system according to claim 1 wherein theexhaust area/intake area ratio is from 50% to 65%.
 7. The systemaccording to claim 1 wherein squish areas are provided along thecombustion chamber periphery between each pair of adjacent valves, asquish area between said intake valves having an area greater than asquish area between said exhaust valve and an adjacent intake valve. 8.The system according to claim 1 wherein said two intake valves havesubstantially equal areas.
 9. The system according to claim 1 whereinsaid ignition means comprises a single spark plug located in said headsubstantially on said cylinder axis.
 10. The system according to claim 1wherein said ignition means comprises at least three spark plugs. 11.The system according to claim 10 further including a fourth spark pluglocated in said head substantially on said axis of said cylinder. 12.The system according to claim 1 wherein each of said valves issubstantially circular and the ratio of diameters of the intake valvesto the diameter of the exhaust valve is approximately 1:1.
 13. Thesystem according to claim 1 wherein each of said valves is substantiallycircular and the ratio of diameters of the intake valves to the diameterof the exhaust valve is approximately 1:1.2.
 14. The system according toclaim 1 wherein the exhaust area/intake area ratio is approximately 50%.15. The system according to claim 1 wherein the exhaust area/intake arearatio is approximately 65%.
 16. An improved combustion chamber systemfor use with internal combustion engine having at least one cylindereach having a piston and a cylinder head forming a combustion chambertherebetween, comprising:three valves in the head at each combustionchamber, the valves being arranged around the axis of the cylinder; twoof said valves having substantially equal areas and adapted to act asintake valves; the third of said three valves having an areasubstantially equal to, or slightly greater than, the area of one of theintake valves, the third valve being adapted to act as an exhaust valve;said two intake valves positioned closer to each other than to saidexhaust valve; and said head having three approximately hemisphericalrecesses, each of the recesses housing one of the valves.
 17. The systemaccording to claim 16 further including an ignition means comprising asingle spark plug located in said head approximately at the cylindercenterline.
 18. The system according to claim 16 wherein said ignitionmeans comprises at least three spark plugs.
 19. The system according toclaim 18 further including a fourth spark plug located in the headsubstantially on the central axis of said cylinder.
 20. The systemaccording to claim 16 further including squish areas are provided alongthe combustion chamber periphery between each pair of adjacent valves,the squish area between said intake valves having an area greater thatthe squish area between said exhaust valve and an adjacent intake valve.21. The system according to claim 16 wherein each of the valves issubstantially circular and the ratio of diameters of the intake valvesto the diameter of the exhaust valve are from 1:1 to 1:1.2.
 22. Thesystem according to claim 16 wherein the head includes three hemisphericdepressions each housing one of the valves.
 23. The system according toclaim 16 wherein the exhaust area/intake area ratio is from 50% to 65%.24. The system according to claim 16 wherein each of the valves issubstantially circular and the ratio of diameters of the intake valvesto the diameter of the exhaust valve is approximately 1:1.
 25. Thesystem according to claim 16 wherein each of the valves is substantiallycircular and the ratio of diameters of the intake valves to the diameterof the exhaust valve is approximately 1:1.2.
 26. The system according toclaim 16 wherein the exhaust area/intake area ratio is approximately50%.
 27. The system according to claim 16 wherein the exhaustarea/intake area ratio is approximately 65%.
 28. An improved combustionchamber system for use with internal combustion engine having at leastone piston and a cooperating cylinder head forming a combustion chambertherebetween, which comprises:three valves in the head at the combustionchamber, said valves being arranged around the axis of the cylinder; twoof said valves having substantially equal areas and adapted to act asintake valves; the third of the valves having an area substantiallyequal to, or slightly greater than, the area of one of the intakevalves, the third valve being adapted to act as an exhaust valve; saidtwo intake valves being spaced a greater distance from said exhaustvalve than from each other; said piston having a generally planarsurface adjacent to said head forming one wall of the combustionchamber; and two spark plugs located between said exhaust valve and eachof said intake valves, said spark plugs located outside of a line drawnbetween the center of said exhaust valve and the center of thecorresponding intake valve.
 29. The system according to claim 28 whereinsquish areas are provided along the combustion chamber periphery betweeneach pair of adjacent valves, the squish area between said intake valvesbeing less than the squish area between said exhaust valve and anadjacent intake valve.
 30. The system according to claim 29 wherein eachsquish area between said exhaust valve and an intake valve has asubstantially straight edge portion, said straight edge portion beingapproximately parallel to a line drawn between the centers of saidexhaust valve and an intake valve.
 31. The system according to claim 28wherein said intake valves and spark plugs are symmetrically located onthe sides of a line drawn through the center of the exhaust valve andequally spaced between the intake valves.
 32. The system according toclaim 28 wherein each of the valves is substantially circular and theratio of diameters of the intake valves to the diameter of the exhaustvalve are from 1:1 to 1:1.2.
 33. The system according to claim 28wherein said head includes three hemispheric depressions each housingone of said valves.
 34. The system according to claim 28 wherein theexhaust area/intake area ratio is from 50% to 65%.
 35. The systemaccording to claim 28 wherein each of the valves is substantiallycircular and the ratio of diameters of the intake valves to the diameterof the exhaust valve is approximately 1:1.
 36. The system according toclaim 28 wherein each of the valves is substantially circular and theratio of diameters of the intake valves to the diameter of the exhaustvalve is approximately 1:1.2.
 37. The system according to claim 28wherein the exhaust area/intake area ratio is approximately 50%.
 38. Thesystem according to claim 28 wherein the exhaust area/intake area ratiois 65%.